Four brassy broads roll up their sleeves and do the heavy lifting in “The Fabulous Four,” an old friends reunite for a Key West wedding comedy from the director of “How to Make An American Quilt.”

Their efforts are largely for naught as this turns out to be yet another underscripted comedy for players who have their AARP cards, aimed at an audience that also has theirs.

If you can’t get laughs out of Bette Midler, Megan Mullally, Sheryl Lee Ralph and Susan Sarandon, that’s on you, Anne Marie Allison and Jenna Milly (they wrote “Golden Arm” together).

But director Moorhouse, who first gained notice as a producer on her husband’s “Muriel’s Wedding,” finds some heart and room for tunes in this story of strained friendships, bad behavior and last chance romance set in Key West, but largely shot in Georgia.

And if you don’t grin at the sight and sound of Midler, Ralph (a “Sister Act 2” veteran now seen on TV’s “Abbott Elementary) and Mullally singing Jimmy Cliff’s “I Can See Clearly Now” while parasailing above the Hawk Channel, that’s on you.

Marilyn and Lou (Midler and Sarandon) were roomies in college and afterwards in New York City, where Kitty (Ralph) and Alice (Mullally) were their neighbors.

Decades have passed, with Lou becoming a hyper-focused and still-single surgeon, Alice a backup singer who never grew up, Kitty a widowed organic pot farmer and Marilyn a newly-widowed housewife of means.

Moving from Atlanta to Key West after her husband’s death did Marilyn more good than she’d expected. Now, she’s summoning her posse from way backwhen to her hastily-arranged wedding.

Free spirits Alice and Kitty are happy to oblige. But there’s been bad blood between Marilyn and Lou. So the other two have to trick her into making the trip by telling cat lady Lou she’s won a Hemingway polydactyl (six-toed) kitty, one of the descendents of Hemingway’s own cats from the Hemingway House, now a museum in Key West.

Once there, fences can be mended as they’ll all stay at Marilyn’s beachside mansion and the two feuders will be forced to make nice for dress-fittings, dinners and entertainment Marilyn has lined up.

The script’s logic flies out the window with all this as Lou simply ignores — or seems to — the fact that her friends lied to her and Marilyn was the offending party and isn’t apologizing for her offense. Still. Marilyn is all “Everything’s fine, now” even though she only planned for two guests, and that leaves Lou as odd-woman out in things like “three person parasailing.”

Lou’s loner status and sex life are discussed, with remedies (sex aids, gummies, etc.) by Alice and Kitty. She keeps running into three very young and dizzy bridesmaids-with-their-bride whom she met on the flight down, who are are “Woo hooing” their way through a Key West weekend.

And Lou meets this “silver fox” whose stolen bike she recovers with a sex toy turned into a weapon. He’s a charming bar owner and Hemingway fan played by Bruce Greenwood.

All the seniors in the island city seem to quote Papa Hemingway by heart, hit the historic bars and not the tourist traps and meet up for a Michael Bolton front porch concert, pre-wedding.

And the ladies? Man-eater Alice devours any edible and any male who crosses her path, Kitty is contending with a newly-divorced daughter who has fallen into a conservative cultish church, which has her rejecting her gay son, Marilyn is feeding a new Tik Tok obsession and Lou has to let it all roll off her back as the lone “Act your AGE” adult in the room.

Every element in this script is generic and lazy, from Lou’s “Dr. Love” bike-jacking video going “viral” to the romantic “twists” in the plot as regards her feud with Marilyn.

Midler, Sarandon, Ralph and Mullally throw themselves at this material as if they can will it to life. And while watching each — and Greenwood — is always a pleasure, this is as limp most of the other rom-coms aimed at this age group (often starring Diane Keaton) tend to be these days.

It’s as if Hollywood sees something tailor-made for players perceived to still have box office value and a following (Midler is a hoot on Twitter), and then doesn’t bother workshopping the script until it’s worthy of their legendary talents.

The film’s grasp of Key West — some second unit and perhaps first unit footage was shot there — is slippery, sending the quartet to dinner at the Hemingway House restuarant (the museum doesn’t have one, nor is there one on the property), showing us a taste of Duval Street and the famed Key West chickens and landmark bars and aerial shots of Mallory Square, but not capturing the evening sunset spectacle and celebration.

“The Fabulous Four” thus tumbles into that famous Key West aphorism, related to any visitor, going back decades, to suggest the good times they’ve missed.

“You should’ve been here 20, 30 or 40 years ago” the old saying goes, before the cruise ships took over from the gays who took over from the Conchs who inherited the place from the Navy who set up shop here after the wreckers, etc.

Our stars may be timeless, but you should’ve seen them when they commanded more control of their projects than this and could demand the rewrites this tepid typewritten treacle needed.

Rating: R, drug abuse, profanity, innuendo

Cast: Bette Midler, Susan Sarandon, Sheryl Lee Ralph, Bruce Greenwood and Megan Mullally.

Credits: Directed by Jocelyn Moorhouse, scripted Anne Marie Allison and Jenna Milly. A Bleecker Street release.

Running time: 1:38